A time series is a repeated measurement, estimate, or other indication of a magnitude or other value taken generally at predetermined time intervals over an extended time frame. Examples of time series are annual population figures for a selected geographic area, the gross national product for a particular country on an annual, quarterly or monthly basis and the like.
Time series currently represent one of the largest data bases of historical and current information on economic, social, resources, environmental and political conditions, and other subjects. However, to effectively use such time series, and more particularly to turn such time series into information useful in making decisions, forming opinions, and making projections, effective techniques must be provided not only for permitting the user to quickly and easily retrieve all of the available time series relevant to his particular problem, but also for permitting the user to perform a variety of transformations and other manipulations on such time series to develop additional useful information. It is also desirable that all available time series information, both the originally stored time series and time series generated as a result of manipulations on the raw data, be present in a form which permits the user to easily perceive relationships, trends and the like in the data. While the graphic capability which now exists in most computers permits the user to more easily perceive relationships, new tools are required to permit the effective utilization of such capabilities. Further, since the user frequently does not know what he is looking for until he finds it, the system should be organized to assist the user in locating useful data. In addition, since old patterns of thought and expectations ma limit the user's ability to find what he needs or perceive useful relationships, the system should assist the user in being creative in the use of the available data to achieve his desired objectives. Thus, the system should provide guidelines for the use of the time series data, but permit the user to make all decisions in using the data. The amount of information which the user receives at each point on which to base decisions should also be limited so as to avoid user confusion from choice overload, thus making it easier for the user to make decisions. In addition, the system should preferably be free standing with all catalog entries in the system rather than in a separate written catalog. This, among other things, makes it easier for the catalog to be updated to reflect entries made by the user. It is also easier for the user to make catalog selections from an entry title shown in the context of its topics rather than merely from a code for the time series from, for example, a written catalog as is the case for some prior art systems.
Further, the user should be permitted to reconfigure the data to his requirements rather than being limited by the rigid file structure of prior art systems where new data bases for the system must be purchased to get data in a different form. Thus, once the user has collected all of the time series relevant to his problem, both originally stored time series and time series generated as a result of manipulations by the user on the original data, such information should be stored and cataloged in a manner such that it may all be retrieved quickly either as a single block or as desired time series rather than requiring the user to separately locate and to again retrieve each of the individual original time series and to either regenerate series resulting from manipulations on this data or to locate and retrieve each such generated series from the location where it was stored. Further, in order to convert the time series into useful information, it is desirable that the technique utilized be adapted to quickly and easily convert the raw data to, for example, a per capita basis or to adjust annual financial figures for inflation (i.e., express in constant dollars). Finally, additional useful information can frequently be obtained from time series by performing certain moving transformations thereon which moving transformations have not heretofore been available. Such moving transformations include, but are not limited to, moving variance or moving standard deviation on a single time series, and moving covariance or moving correlation between two or more time series.
While systems currently exist which are adapted to access, display and perform certain manipulations on time series, none exist which are capable of effectively performing the various functions indicated above.
It is therefore an object of this invention to provide an improved method and apparatus for facilitating the retrieval of all time series in a collection of time series which are relevant to the solution of a particular problem.
Another object of this invention is to permit the retrieved time series to be transformed or otherwise manipulated, and in particular to permit certain moving transformations to be performed on such data and to facilitate the transformation of such data to a adjusted for-inflation, per capita, or other converted form.
Still another object of this invention is to permit the time series resulting from a transformation or manipulation of the original data to be separately stored and to facilitate the easy retrieval of all time series, both originally selected time series and time series generated as a result of manipulations, which time series are relevant to the solution of a particular problem.